Herein, we report the synthesis and biological evaluation of three novel halogenated 6-substituted 4-anilinoquinazoline based EGFR-TKIs. Radiosynthesis (I-125 and F-18) of the corresponding analogues was
also performed.
Methods: 6a, 6b and 8 were obtained by reaction of 6-amino-4-anilinoquinazoline (5) with 3-/4-iodobenzoyl and 4-fluorobenzoyl chlorides. Inhibition selleck chemical of EGFR autophosphorylation and A431 cellular proliferation were assessed by Western blot and MTT assays. I-125-anilinoquinazolines [I-125]6a/b were prepared via destannylation of the corresponding tributylstannyl precursors with [I-125]Nal. Cellular uptake studies were conducted in A431 cells. Optimization of the radiosynthesis of the F-18-anilinoquinazoline [F-18]8 was attempted by nucleophilic substitution of the trimethylammonium- and nitro-6-substituted 4-anilinoquinazoline CH5183284 precursors.
Results: 6a, 6b and 8 were synthesized in high chemical yield. All of them are inhibitors of EGFR autophosphorylation (0.1<IC50<1 mu M) and A431 cell proliferation (IC50<3.5 mu M). [I-125]6a/b, obtained in high radiochemical purity and specific
activity, were highly taken up by A431 cells. Biodistribution profile in mice indicated fast blood clearance and hepatobiliary excretion. Despite all attempts, [F-18]8 was only formed in 4% yield, hampering further biological evaluation.
Conclusions: This study suggests that these quinazoline derivatives can act as EGFR-TKI, warranting further modifications in the chemical structure in order to be explored as potential molecular imaging agents for single photon emission computerized tomography and positron emission tomography. (C) 2012 Elsevier Inc. All rights reserved.”
“Expressed protein ligation (EPL) is an intein-based approach that has been used for protein engineering and biophysical studies of protein structures. One major problem of the EPL is the low yield of final ligation product, primarily due to the complex procedure of the EPL, preventing EPL from gaining popularity in the research community. Here we report
an efficient on-column EPL strategy, which focuses on enhancing the expression level of the intein-fusion protein that generates thioester for the EPL. We applied this EPL strategy to human apolipoprotein E (apoE) and routinely obtained 25-30 mg segmental, triple-labeled Wilson disease protein apoE from 1-L cell culture. The approaches reported here are general approaches that are not specific for apoE, thus providing a general strategy for a highly efficient EPL. In addition, we also report an isotopic labeling scheme that double-labels one domain and keeps the other domain of apoE deuterated. Such an isotopic labeling scheme can only be achieved using the EPL strategy. Our data indicated that the segmental triple-labeled apoEs using this labeling scheme produced high-quality, simplified NMR spectra, facilitating NMR spectral assignment.